Defective ignition coils?

I recently bought a Yamaha XJ 600 -84 non-runner. The electrical system is a corroded mess. The bike was supposedly running a few years back... When I tried to measure the ignition coils, I get no contact, on either of them (2), from the HT end to any of the low voltage connections. I have never before come across a bike with both ignition coils faulty at the same time, so my question is this; Is there maybe some very high Ohm resistor, or some spark gap on the output (HT) end of the coils that makes it impossible to check the coils this way?
Thanx in advance,

Erik